Cosmetic Bottle with Splash

The instructions on this page guide you through the process of setting up a simulation of water pouring on a cosmetic bottle that generates many of liquid splashes. We also take advantage of the new VoxelShader helper to create whitewater in the liquid.

This simulation requires at least Phoenix 5.0 and V-Ray 5, Update 2.3. You can download official Phoenix and V-Ray from https://download.chaos.com. The scene can be rendered in both V-Ray 5 and V-Ray 6, but due to some differences between the two versions, some of the materials will render slightly different. To achieve the exact same end result as in the tutorial, you will need to use V-Ray 6. You can download your desired Phoenix and V-Ray versions from the downloads page.

If you notice a major difference between the results shown here and the behavior of your setup, please reach us using the Support Form.

The Download button provides you with an archive containing the scene files.

Download Project Files

Scale is crucial for the behavior of any simulation. The real-world size of the Phoenix Simulator in units is important for the simulation dynamics. Large-scale simulations appear to move slower, while mid-to-small scale simulations show a lot of vigorous movement. When you create your Simulator, inspect the Grid rollout where the real-world extents of the Simulator are shown. If the size of the Simulator in the scene cannot be changed, you can cheat the solver into working as if the scale is larger or smaller by changing the Scene Scale option in the Grid rollout.

Go to Customize → Units Setup and set the Display Unit Scale to Metric Centimeters.

Also, set the System Units so that 1 Unit equals 1 Centimeter.

The final scene consists of the following elements:

1. A Phoenix Liquid Source;
2. A Phoenix Liquid Simulator;
3. A V-Ray Physical camera;
4. Two V-Ray Lights for lighting;

5. A Box001 geometry used as emitter in the Liquid Source;

6. Box002~004 geometries as colliders or deflectors;

7. A Cosmetic_bottle geometry;

8. A Cosmetic_cap geometry;
9. A VoxelShader helper;

Select the front side of the Box001, and set those polygons' face IDs to 2. This limits the fluid emission to only one side of the box. 

Add a Noise modifier to make the fluid emission more dynamic. Adjust its settings:

Put three extra boxes around Box001, the liquid emitter. Box002 and Box003, which are situated at the sides of the emitter, play an important role for making the liquid stream thicker at its edge. Box004 serves as a deflector under the emitter.

Go to the Time Configuration and set the Animation Length to 90 so that the Time Slider goes from 0 to 90.

The image here is from the final render of this tutorial.

The frame is from the beginning of the animation, before the water touches the bottle. You can see the liquid takes on a tongue shape at its end. The two edges of the water splash are thicker than the middle.

As the water pours on the bottle, the bottle flips and you can see strongly rebounding splashes. Whitewater shading is also visible, as well as some droplets on the bottle.

Go through the steps of this tutorial to see how to build these features.

Let's create a Liquid Simulator. Go to Create Panel → Create → Geometry → PhoenixFD → PhoenixFDLiquid.

The exact position of the Simulator in the scene is XYZ: [ 5.25, 31.0, 61.0 ].

Open the Grid rollout and set the following values:

Open the Output rollout and enable the Particle Velocity, Particle ID, Grid Liquid, and Grid Velocity. Set the Special channel to Vorticity Smooth.

Add a Liquid Source from Helpers → Phoenix FD → Liquid Source.

The Liquid Source is a Phoenix helper node. It determines which objects in the scene the Simulator emits from, how strong the emission is, etc.

Add the Box001 geometry to the Emitter Nodes list.

Once the emitter is added, set the Outgoing Velocity to 200.0cm.

Set the Emit Mode to Surface Force. This will make the object emit only from its surface area.

Set the Polygon ID to 2.

At this stage, you don't need to simulate the full length of the animation. You only need a sample. Go to the Simulation rollout and set the Stop Frame to 30.

Press the Start button to simulate.

Go to the Preview rollout, and enable Show Mesh. Disable all other Voxel Preview channels, so they don't interfere.

Select the Simulator, and go to the Rendering rollout. In the Mesh Smoothing section, increase the Smoothness to 5.0. Enable the Use Liquid Particle option. Set the Particle Size to 1.0.

Here is a preview animation of the simulation so far. You can see the liquid mesh is too noisy. The mesh is torn and chaotic.

To make the liquid look less noisy and smoother, select the Simulator, and go to the Dynamics rollout. Increase the Steps Per Frame to 4.

With the new settings, run the simulation again.

Here is the simulation at this step. Now the liquid mesh is much smoother.

Water is a Newtonian fluid, so you need to adjust the surface tension settings to make it more realistic.

With the Simulator selected, go to the Dynamics rollout, and in the Surface Tension section:

Run the simulation again.

This is the simulation up to this step.

With the new Surface Tension settings, the flow appears thicker and the morphology is more suitable for a Newtonian fluid.

To make the pouring water bounce stronger when hitting the bottle, adjust the cosmetic geometries' Motion Velocity Effect.

Select both the Cosmetic_bottle and Cosmetic_cap. Right click and select Chaos Phoenix Properties. Increase the Motion Velocity Effect to 6.0.

Run the simulation again.

Now the rebounding liquid splashes are stronger as the cosmetic bottle flips. This makes the shot more dramatic.

To allow liquid to stick on the bottle, go to the Dynamics rollout of the Simulator. Enable the Wetting option. Set the Sticky Liquid to 0.6.

Here is a preview animation of the simulation.

Although Wetting is enabled, barely any droplets adhere on the surface of the bottle.

Select the Liquid Simulator, and go to the Dynamics rollout. Set the Default Viscosity to 0.03.

Here is a preview animation of the simulation.

Now the droplets temporarily adhere to the bottle.

To make the shot more cinematic, let's add a bullet time effect to the liquid. As Phoenix allows animation of the Time Scale parameter directly, you can just set key frames to the Time Scale.

To simulate the full length of the simulation, enable the Timeline of the Stop Frame.

Go to Graph Editors/Track View → Curve Editor and set key frames to the curve of the Simulator's Time Scale. Setting keyframes to the Time Scale gives the animation a period of bullet time effect. Each frame and value is shown in the screenshots. All keyframes are set to Tangents to Linear.

Run the simulation again.

Here is a preview animation of the simulation.

Now the bullet time effect makes the shot more interesting. However, when time slows down, the droplets aggregate and grow larger in an unrealistic way.

During the bullet time effect, it is unnecessary for the Steps Per Frame option to have a high value. Animate Steps Per Frame according to the keyframes of the Time Scale.

The Steps Per Frame option is located in the Dynamics rollout of the Simulator.

Go to Graph Editors/Track View → Curve Editor and set key frames to the curve of the Simulator's Steps Per Frame (SPF) parameter. Set the SPF keyframes so the Simulator makes less calculations during the bullet time effect. Each frame and value is shown in the screenshots. All key frames are set to Tangents to Linear.

Run the final simulation.

Here is a preview animation of the simulation. Now the size of the droplets is consistent throughout the animation.

This part of the tutorial focuses on the water material for the liquid.

Create a V-Ray Material. Assign it to the PhoenixFDLiquid Simulator. Set the Diffuse color to black.

Set the Reflection and Refraction colors to white. Set the IOR to 1.333, which is the physically accurate Index of Refraction of water.

Keep the Max depth to its default value of 8 for both Reflection and Refraction.

To slightly blur the specular highlights, produced by the light source in the scene, reduce the Reflection Glossiness to 0.85.

Here is a rendered image with the water material applied to the Simulator. With the black background, it is hard to see the water in the shot. Usually with fast moving liquid, whitewater should be visible within it.

Go to Create Panel → PhoenixFD and create a VoxelShader helper in the scene.

Select the Voxel Shader. In the Modifier Panel, add the PhoenixFDLiquid Simulator to the Voxel Grid source. Switch the Sampler Type to Spherical.

Click on the Volumetric Options button.

In the Volumetric Render Settings of the VoxelShader helper:

Select the Simulator, and go to the Preview rollout. Disable Show Mesh, and enable the Special option, under Voxel Preview. By doing so, Phoenix visualizes the Vorticity data in the viewport.

Here is a rendered image with the Voxel Shader in the scene. A cloud of smoke with no definitive boundaries now covers the liquid.

Select the VoxelShader helper. Go to the Modifier Panel, and add the PhoenixFDLiquid Simulator to the Cutter Geometry source. Enable the Cutter Geometry option.

Here is a rendered image after the last step. The whitewater appears too strong.

Select the VoxelShader helper, and go to the Volumetric Render Settings. Switch the Smoke Opacity type to Based on Smoke.

To reduce the effect of whitewater, adjust the curve of the Smoke Opacity as shown. The Opacity diagram allows you to use the smoke channel and remap it through the Opacity Curve to get the rendered opacity. In this case, the curve remaps the input smoke value to a smaller value. For example, when the input value is 7.5, the output will remap to 0.3. Besides, the curve is tweaked in S-shape making the whitewater looks more contrasty.

Alternatively, instead of manually creating the Smoke Opacity curve yourself, you can load the render preset file from the provided example scene files here. Otherwise, skip this step.

To load the render preset file, press the Render Presets button. It is located under the Rendering rollout of the VoxelShader node. Select Load from file, and open up the VoxelShader_RenderPreset.tpr file.

Open the V-Ray Frame Buffer, and use the Create Layer to add layers for Lens Effects, White Balance, Exposure and Filmic tonemap.

Render the final image using the V-Ray Frame Buffer with the color corrections and post-production effects set to:

Filmic tonemap:

Feel free to use other values for the post-production effects, depending on your preferences.

Here is the final rendered result.